Misfires and multiple codes - can you help?
03-28-2022, 10:45 AM
#1
JK Newbie
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Join Date: Mar 2022
Location: rochester,mi
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Misfires and multiple codes - can you help?
REPORT: ECU Fault Log:
Vehicle Manufacturer: Jeep
Vehicle Calibration ID: 68043457AI7
Current Fault Log------------------
P0401: Exhaust Gas Recirculation Flow Insufficient Detected Pending Fault Log------------------
ECU reports no pending faults Historic Fault Log------------------
ECU reports no historic faults
Other discovered fault codes(possibly pending, current or manufacturer specific)----------------------------------------------------
P0300: Random/Multiple Cylinder Misfire Detected
P0303: Cylinder 3 Misfire Detected
P0306: Cylinder 6 Misfire Detected
P2308: Ignition Coil C Secondary Circuit
End of report.
STORY:
My 2010 JKU started.misfiring, so, after a small investigation, I replaced the ignition coil. Misfires stopped.
Misfires came back 1 week later. Read up.on forums, and they suggested to swap.out the EGR valve, and I did. Misfires didn't go away.
Read up some more, and swapped.out the spark it's and the spark plug wires and no change.
Took it to the mechanic and he suggests to swap out the ECU/ECM which should fix the issue.
Mechanic asking for $950/- for the ECM and another 500/- for labor and programming.
Has anyone encountered this problem before? How did you resolve it? Also, do you think the mechanics recommendation is correct?
Thank you for your help and guidance.
Vehicle Manufacturer: Jeep
Vehicle Calibration ID: 68043457AI7
Current Fault Log------------------
P0401: Exhaust Gas Recirculation Flow Insufficient Detected Pending Fault Log------------------
ECU reports no pending faults Historic Fault Log------------------
ECU reports no historic faults
Other discovered fault codes(possibly pending, current or manufacturer specific)----------------------------------------------------
P0300: Random/Multiple Cylinder Misfire Detected
P0303: Cylinder 3 Misfire Detected
P0306: Cylinder 6 Misfire Detected
P2308: Ignition Coil C Secondary Circuit
End of report.
STORY:
My 2010 JKU started.misfiring, so, after a small investigation, I replaced the ignition coil. Misfires stopped.
Misfires came back 1 week later. Read up.on forums, and they suggested to swap.out the EGR valve, and I did. Misfires didn't go away.
Read up some more, and swapped.out the spark it's and the spark plug wires and no change.
Took it to the mechanic and he suggests to swap out the ECU/ECM which should fix the issue.
Mechanic asking for $950/- for the ECM and another 500/- for labor and programming.
Has anyone encountered this problem before? How did you resolve it? Also, do you think the mechanics recommendation is correct?
Thank you for your help and guidance.
03-28-2022, 12:05 PM
#2
Super Moderator
Welcome to JKF.. Good group are on board here. Much experience and knowledge.. In checking on ECM.. I found this from Mopar.. Module Powertrain control.. Mopar Parts shows: New with a list price of $1,030 and Reman $ 730.. both have a core charge of $125. I did not find any info on availability.. Confirm with your mechanic that this is what he references as ECU/ECM. Hope there is a member who can share more info.
03-29-2022, 01:29 AM
#3
JK Enthusiast
i just had to replace mine...
so, as far as price: wranglerfix is who i went with. they run roughly 750 bucks. should be plug and play. there are three bolts and 2 connectors. so, 500 bucks for labor seems extremely excessive. as far as the PCM: they dont have new. you are gonna have to get a refurb unit.
my original symptoms: ran fine for 15 seconds, then had misfires. had the dreaded p0300 code, o2 sensors showed bad, misfires on cylinders 1, 2, 5.... i replaced: all plugs, coils, o2 sensors, crank sensor, and on and on and on.
finally ended up replacing the PCM. the only issue i had was originally the PCM was for a manual transmission...i have and auto. so the Jeep was "looking" for the clutch to be down....and the Jeep wouldnt start. once that got sorted...worked like a champ.
looking at your codes, since you are getting misfires on separate sides of the engine (3 and 6)...you either have catastrophic failure on your engine (i think you would know that), something wrong with a wire harness that would be common between the 2 sides, fuel delivery...or the PCM.
i would ask a few things: are you "feeling" the misfires? is there a noticeable difference? is the check engine light flashing or just on?
Grab the Jscan app and an OBDII dongle and clear the codes...start up your jeep and see if they come back. see if there are more misfires than just throwing codes (mine had msfires on 1, 2, 5, but only threw the 0300 code...so, the Jscan app really helped)
i have posted this before and will post again: a lot of times, if the pcm went bad, whatever CAUSED it to go bad wasnt addressed...and it will cause the PCM to fail again. meaning: was it a short in your coil wire? if so, the short didnt disappear, and the pcm is an expensive piece to have fail twice or three times.
in going back and re-reading your post....since you said that you got the misfires to go away for a week...this pushes me a little more towards fuel delivery or a wiring issue.
so, as far as price: wranglerfix is who i went with. they run roughly 750 bucks. should be plug and play. there are three bolts and 2 connectors. so, 500 bucks for labor seems extremely excessive. as far as the PCM: they dont have new. you are gonna have to get a refurb unit.
my original symptoms: ran fine for 15 seconds, then had misfires. had the dreaded p0300 code, o2 sensors showed bad, misfires on cylinders 1, 2, 5.... i replaced: all plugs, coils, o2 sensors, crank sensor, and on and on and on.
finally ended up replacing the PCM. the only issue i had was originally the PCM was for a manual transmission...i have and auto. so the Jeep was "looking" for the clutch to be down....and the Jeep wouldnt start. once that got sorted...worked like a champ.
looking at your codes, since you are getting misfires on separate sides of the engine (3 and 6)...you either have catastrophic failure on your engine (i think you would know that), something wrong with a wire harness that would be common between the 2 sides, fuel delivery...or the PCM.
i would ask a few things: are you "feeling" the misfires? is there a noticeable difference? is the check engine light flashing or just on?
Grab the Jscan app and an OBDII dongle and clear the codes...start up your jeep and see if they come back. see if there are more misfires than just throwing codes (mine had msfires on 1, 2, 5, but only threw the 0300 code...so, the Jscan app really helped)
i have posted this before and will post again: a lot of times, if the pcm went bad, whatever CAUSED it to go bad wasnt addressed...and it will cause the PCM to fail again. meaning: was it a short in your coil wire? if so, the short didnt disappear, and the pcm is an expensive piece to have fail twice or three times.
in going back and re-reading your post....since you said that you got the misfires to go away for a week...this pushes me a little more towards fuel delivery or a wiring issue.
Last edited by ballistik_monkey; 03-29-2022 at 01:35 AM.